8
5. Key Dates B.Winter Solstice (Dec 21) 1.Shortest period of daylight in Northern Hemisphere, sun lowest in altitude 2.Rises and sets farther south than any other day 3.Sun’s direct rays are at 23.5º South, directly overhead at Tropic of Capricorn 4.1 st day of winter 5.24 hours of darkness North of Arctic Circle

9
5. Key Dates C.Summer Solstice (June 21) 1.Longest period of daylight in Northern Hemisphere, sun highest in altitude 2.Rises and sets farther north than any other day 3.Sun’s direct rays are at 23.5º North, directly overhead at Tropic of Cancer 4.1 st day of summer 5.24 hours of daylight North of Arctic Circle

13
VII. Seasons A.Caused by the Sun’s rays striking different areas of Earth’s surface B.Reasons for the Seasons 1.Earth REVOLVES around the Sun 2.Earth’s axis is tilted 23.5º 3.Parallelism of the axis (axis stays parallel while it travels around the sun) http://astro.unl.edu/naap/motion1/animations/seasons_ecliptic.html

14
VII. Seasons C.Season do NOT depend on the distance from the sun – orbit is an ellipse! 1.Closest to sun (Perihelion) a.On January 4 th b.91.5 million miles 2.Farthest from Sun (Aphelion) a.On July 3 rd b.94.5 million miles